THE TICKS 



137 



Fig. 76. — Capitulum (rostrum), 

 of an argasid tick: h, hypostome; 

 c, chelicerEe; p, palpi; b, basi.s 

 oapituli. 



al)sent in the Argasidie — is a hai'd, ])lat(-'-like structure localed imuie- 

 diately posterior to the eapituluni. In the male it usually- covers the 



entire, or almost the entire, dorsal surface, 

 in nymphs it covers the anterior portion; 

 while in the adult female it is nmch smaller 

 and confined to the anterioi' portion of the 

 l)od>-. 



S. Dorsum. — This term I'cfei-s to the 

 whole dorsal surface of the Ijody. 



4. Festoons (Fig. 82) ai'e uniform rect- 

 angular areas into which the posterior mar- 

 gin of the body is divided up. Usually 

 elev(>n nia^- be more or less distinctty rec- 

 ognized. They are most distinct in unfed 

 specimens, but almost or <'ntirely disap- 

 pear in distended females. They are not 

 present in all forms. 



5. Pundations are circular depressions 

 upon the integiunent from which fre- 

 cjuently issue hairs. 



6. Ornamentation refers to enamel-like coloration which may Ije pres- 

 ent on the scutum, capitulum, or other parts. Ticks ujion which this 

 coloration occurs are re- 

 ferred to as ornate. 



7. Venter. — This term 

 refers to the whole ventral 

 surface of the body. 



8. The Spiracles (Figs. 

 78 and 78, a) — also called 

 stigmata, stigmal plates, 

 and peritremes — are two 

 respiratory organs sit- 

 uated ventro-laterally. In 

 the Ixodida they are sit- 

 uated posterior to the 

 attachment of the fourth 

 pair of legs; in the Arg- 

 asidffi they are between 

 the third and fourth pairs. 

 The entire structure maj- 

 be considered as the 

 stigmal plate or peritreme 

 with an opening known as 

 the spiracle or stigmal aperture 



Fiii. 77. — Capitulum (head), .~;cutuni (shield), and 

 foreleji of Margaropus annulatus (frr)ni i)hotominro- 

 grajjh of mounted speoinien, }}y Hoedt). 



The stigmal plates vtiry in form and 



